Frequently Asked Questions - Medical applications

Sometimes radioactive substances are administered to patients in hospitals. This is done at the nuclear medicine department. One of the reasons is to visualise certain problems in the body, like tumours, or to treat them.
When a patient is injected with a radioactive pharmaceutical, he will emit radiation. The level of radiation will decrease in time, because the patient excretes the radioactive compount in his urine, and because the radioactivity decreases during radioactive decay. Patients are only allowed to leave the hospital after the radiation level has decreased below a certain level. At that moment, it is not dangerous for bystanders to be near the patient.
It is still recommended that the patients sleeps alone for a few days, and that he should not take small children on his lap. These simple rules, that a patient receives from his hospital, help to decrease the radiation exposure of bystanders even more: more distance means less radiation dose. Little children are more sensitive to radiation, that is the reason to keep some extra distance.
To make a long story short: it is no problem to take your children to visit their grandfather, but it is better not to have them cuddle their grandfather for too long.

X-rays are ionising (nuclear) radiation, just like gamma radiation. Too much exposure may lead to biological harm. The radiation exposure of one or two X-ray pictures does not give any increase of risk, but a dentist shoots hundreds of X-ray pictures per year. It is better not to be exposed every time, if it is not really needed. That is why a dentist stands in a different room when making the pictures.